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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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An Advanced Cooling Device for Concentrated Photovoltaic Systems

Concentrated photovoltaics (CPV) have the potential to significantly enhance the energy conversion utilization of solar panels and reduce solar generation costs, making them a crucial area of advancement in solar power generation technology. However, the concentration of sunlight can lead to overheating of solar panels, resulting in a notable reduction in both the efficiency of solar power generation and the lifespan of the panels. This challenge remains the predominant technical hurdle that hinders the application of concentrated photovoltaic power generation technology. In this study, we propose a new cooling method for concentrated photovoltaic power generation systems via an integrated approach of incorporating Phase-Change Thermal Storage (PCTS) and Thermoelectric Generator (TEG) technology. This new method not only enhances the overall system's electricity generation efficiency but also effectively resolves the technical challenge of concentrated photovoltaic panel overheating issues, ensuring the continuity of concentrated photovoltaic power generation and extending the lifespan of solar panels and their components. In order to make full use of the wasted heat generated by photovoltaic power generation and effectively improve the power generation efficiency of the system, this work developed a phase change heat storage device based on a phase change material. This device uses the temperature difference between day and night to recover wasted heat from photovoltaic power generation. Through integration with the thermoelectric power generation system, thermal energy can be converted into electrical energy. In addition, the Peltier effect of thermoelectric materials is used to construct a photovoltaic panel overheating protection system, which significantly improves the reliability and service life of the system.

14 SOLAR ENERGY↗

An Advanced Cooling Device for Concentrated Photovoltaic Systems

Concentrated photovoltaics (CPV) have the potential to significantly enhance the energy conversion utilization of solar panels and reduce solar generation costs, making them a crucial area of advancement in solar power generation technology. However, the concentration of sunlight can lead to overheating of solar panels, resulting in a notable reduction in both the efficiency of solar power generation and the lifespan of the panels. This challenge remains the predominant technical hurdle that hinders the application of concentrated photovoltaic power generation technology. In this study, we propose a new cooling method for concentrated photovoltaic power generation systems via an integrated approach of incorporating Phase-Change Thermal Storage (PCTS) and Thermoelectric Generator (TEG) technology. This new method not only enhances the overall system's electricity generation efficiency but also effectively resolves the technical challenge of concentrated photovoltaic panel overheating issues, ensuring the continuity of concentrated photovoltaic power generation and extending the lifespan of solar panels and their components. In order to make full use of the wasted heat generated by photovoltaic power generation and effectively improve the power generation efficiency of the system, this work developed a phase change heat storage device based on a phase change material. This device uses the temperature difference between day and night to recover wasted heat from photovoltaic power generation. Through integration with the thermoelectric power generation system, thermal energy can be converted into electrical energy. In addition, the Peltier effect of thermoelectric materials is used to construct a photovoltaic panel overheating protection system, which significantly improves the reliability and service life of the system.

Gou, Yimeng↗

HEX 2-piece ID Absorber: Steady and Transient Thermal FEA

Radiation fans from Insertion Devices and Bending Magnets are “trimmed” by various water-cooled absorbers located strategically downstream of those sources. Mostly, the absorber surfaces onto which power is deposited are constructed from Glidcop Al-15 (rarely OFHC copper). On the basis of Tech Note 327 a re-design for improved thermal performance has evolved to a two-piece ID Absorber configuration; one between dipole chamber and quadrupole, another after the sextupole, each with reduced incident angle. The ring’s Active Interlock (AI) system protects against overheating by disabling mis-steered beam within an allotted time. SRP (Synchrotron Radiation Protection) protocol has a limiting maximum allowable temperature of 100*C at any point when subject to mis-steered beam for a fixed period before AI activation. After 0.2 msec, radiation exceeding +/- 0.5mm offset and +/- 0.25 mrad angular error from the HEX SCW will trip in fault. AI specification allows 1.0 msec to fully dump the electron beam.

36 MATERIALS SCIENCE↗

The Recent Improvements of the SNS Extraction Kicker Power Supplies

A total of 14 extraction kickers., with one as the hot spare., are in service to extract protons out of the storage ring at the SNS. The jitter issue and the short lifetime of the switches were resolved after the thyratrons were replaced with solid state switches in 2018. This paper discusses the recent improvements. Two thyristor switches suffered overheating damage in separate incidents. One was due to the oil pump failure and the other was the result of a disconnected oil hose. An ultrasonic flow meter and a fiber optic temperature monitoring system have been installed for each extraction kicker power supply. The flow meter continuously monitors the entire tank oil flow. The temperature monitor detects the thyristor switch real-time temperatures in three locations. Fault thresholds are selected so that the thyristor switches are protected from overheating damage. Alarms are configured to alert staff to take actions before faults occur. In addition., the cause of an intermittent misfire issue was identified, and the solution was implemented. Lastly., a future oscilloscope upgrade and an oil level sensor are discussed.

Tan, Yugang↗

Metal-Insulation REBCO Pancake Coil With Solder Surface Shunt: Testing and Modeling

Rare-earth barium copper oxide (REBCO) high-temperature superconducting (HTS) magnets can generate very high magnetic fields with superior engineering current density and robust mechanical integrity. The no-insulation (NI) winding technique, including its metal-insulation (MI) variant, enables “self-protection” against localized overheating through inter-turn current sharing, improving defect tolerance and allowing temporary current overloads. In REBCO pancake coils, the current-sharing path is predominantly confined to the edges of the REBCO tapes due to insulating buffer layers. Applying a surface shunt using solder can effectively enhance current sharing in NI/MI coils via the REBCO tape edges. Here, in this paper, we present both experimental and numerical research on the current distribution in surface-shunt metal-insulation (SSMI) REBCO pancake coils. We tested a stainless steel co-wound MI REBCO double-pancake coil, before and after applying a soldered surface shunt, in a saturated liquid nitrogen bath. The SSMI coil was modeled using the H-formulation and rotated anisotropic resistivity to study its dynamic behavior, including inter-turn current sharing and intra-turn screening currents. Benchmarked by experimental data, the numerical model is able to study the defect tolerance of the SSMI coil during energization.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Effects-Based Monitoring of Geomagnetically-Induced Current Using a Convolutional Neural Network

Geomagnetically-induced current (GIC) due to space weather can flow in the power grid causing undesirable effects such as transformer overheating, misoperation of protection devices, and potential blackouts. It is therefore important to monitor GIC in the power grid to improve online situational awareness and decision-making of system operators during a geomagnetic disturbance. To avoid the costly installation of GIC monitors at transformers’ neutrals, it is desirable to find correlations between GIC and already-monitored parameters. Hence, this work proposed the use of a convolutional neural network (CNN) to compute GIC amplitudes from learned patterns in the time-series data of transformer even harmonic currents. Using an electromagnetic transient program, GIC injection simulations were performed for a modeled Dominion Energy Virginia (DEV) substation with two 504 MVA, 500/230 kV transformers. Data collected from these offline simulations were used to train the CNN to provide online GIC monitoring. Testing the CNN performance involved using real GIC measurements from published literature and from a physical GIC monitor in the DEV area. Finally, the results showed that the proposed method was able to provide GIC readings with a root mean squared error of 1.56 A/phase (equivalent to an average accuracy of 94%) for these real GIC waveforms.

42 ENGINEERING↗

Upgrade of the mechanically pumped CO 2 two-phase cooling system for the alpha magnetic spectrometer on the international space station

This study describes the successful upgrade of a mechanically pumped CO 2 two-phase cooling system in space by designing a new pump module for the Alpha Magnetic Spectrometer-02 on the International Space Station. Key factors for mission success are emphasized, including achieving high coolant filling accuracy within 10% of the target and maintaining system stability within ±1 °C. The impact of adding radiators to improve cooling efficiency is examined, and it is found that operating multi-radiators out-of-phase does not significantly affect system reliability. The centrifugal pump design is shown to allow for better lubricant circulation, while the in-house designed controller incorporates protective measures to prevent cavitation, overheating, and over-current. Further, this research advances the understanding of circulation loop systems and their upgrades in space and demonstrates the potential for extending the lifetime of space-borne mechanically pumped two-phase cooling systems.

42 ENGINEERING↗

The 2023 Gold Run in the Injectors

RHIC Run 23 used Gold beam from Tandem with an AGS extraction energy of 9.8 GeV. The same basic setup, 8 single bunch transfers from the Booster and a 12-6 merge in the AGS to provide 4 bunches at extraction, had been used before to deliver Tandem Au to RHIC. But in those cases, it was used for low energy runs (3.85 GeV in 2021 and 5.75 GeV in 2020) where extraction was below transition energy (7.9 GeV). Tandem beam was used for this run because the intensity and stability of EBIS Au did not meet the requirements for RHIC. Physics was first declared in RHIC on May 22 nd and on August 1 st the run was cut short by about 2 months due to a major failure in RHIC. Prior to the advent of EBIS as the preinjector in 2012, 9.8 GeV Tandem Au was regularly delivered to RHIC but the setup in the Booster and AGS was quite different: Four Booster transfers of 6 bunches each were merged into 4 bunches using a 24-12-4 merge scheme. The supercycle length was 6.0 sec before June 29 th when it was extended to 6.6 sec to accommodate EBIS commissioning. The Tandem, Booster, and AGS were on user 1 for the 9.8 GeV setup. Some work with EBIS Au 32+ took place on EBIS, Booster, and AGS user 5 using the standard 9.8 GeV injector setup with a 4 to 1 merge in Booster and a 6-3-1 type merge in AGS. The Siemens motor generator was used for the entire run. An intensity limit of 8.0e9 Au 77+ ions in the AGS was in effect during the run to protect the J7 plunging stripping foil and the Copper absorber of the AGS beam dump. This corresponds to a merged bunch intensity limit of 2.0e9 Au 77+ ions for 4 equal intensity bunches. The per bunch intensity limit can be increased to 2.67e9 by reducing the number of BtA transfers from 8 to 6. There was also a Booster Late intensity limit of 16e9 Au ions in effect to protect the BtA stripping foil from damage due to overheating. Lowering the number of transfers also makes this limit less of a constraint. BtA foil 5, which was installed in 2020 and had not been used regularly prior to this run was used all run and showed no obvious signs of deterioration. In May, a Tandem Au 3.85 GeV setup from 2021 was also re-established on AGS user 2. It was used for APEX on May 24 and July 26. Initial work with 3.85 GeV beam was on May 19. Proton beam was also set up during the run and extracted to W dump on July 10. It was used for APEX on July 12. Although the OPPIS source was used the AGS setup was without snakes.

43 PARTICLE ACCELERATORS↗

Analysis of water–energy nexus and trends in support of the sustainable development goals: A study using longitudinal water–energy use data

Water and energy are two critical natural resources necessary for human activities and socioeconomic development. Water and energy systems are highly interdependent, and water efficiency and energy efficiency are two related indicators for the United Nations' Sustainable Development Goals. It is critical to improve energy–water use efficiency to sustain socioeconomic development while reducing adverse effects on natural resources, society and the environment. By using longitudinal energy–water use data for China over the past 21 years, this paper develops a temporo-spatial study to address key issues and introduce analytical approaches needed to understand the water–energy nexus and support integrated resource planning and management to achieve the Sustainable Development Goals. Decomposition analysis indicates that the production effect was the dominating factor contributing the increase in the country's energy–water use, while energy–water efficiency is the major factor slowing the growth of the country's energy–water use. Changes and trends analyses show that the country's energy intensity, water intensity, and water/energy ratio significantly decreased from 1999 to 2019, but the rate of decline has slowed. The disparities of the country's provincial energy intensities, water intensities, and water/energy ratios significantly decreased with economic growth. Results suggest that improving energy–water efficiency is critical for the country to curb increasing energy and water use and achieve resource and environmental protection targets with rapid economic development. Furthermore, the disparities between regional energy-water efficiencies can be reduced along with economic growth, while an overheated economy can widen the disparities and result in unsustainable and inefficient utilization of resources. Government coordination, targets and policy as part of the efficiency governance system are critical for continuous energy–water efficiency improvement and directly influence the implementation and effectiveness of energy–water efficiency policy.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

Thermal Energy Grid Storage (TEGS) Using Multi-Junction Photovoltaics (MPV) (Final Technical Report)

The project aimed to develop a thermal energy storage battery that converts electricity to heat and stores heat at ultra-high temperatures (>2000°C) in graphite blocks. The thermal battery discharge uses TPV cells that directly convert thermal energy to electrical energy without any moving parts. All components of this technology were successfully demonstrated at the laboratory scale in this project. Development of extremely low cost (< $20/kWh) grid level energy storage is a crucial necessity to reach high penetrations of renewables. The thermal battery technology developed in this project is expected to meet the cost targets that would enable full renewable penetration. The project focused on four key aspects of this technology: Converting electricity to ultra-high temperature heat: This was done through development of graphite Joule heaters. Major issues related to arcing, heater evaporation and deterioration due to long term oxidation were addressed to ensure lifetime exceeding the service lifetime of the battery. Converting ultra-high temperature heat back to electricity: This was done through development of beyond state-of-the-art TPV cells. We demonstrated energy conversion efficiency of >40% that is a world record and exceeds the average energy conversion efficiency of turbines in the USA. The findings are peer-reviewed and published in Nature, and received a wide media attention globally. Protecting the TPV cells to ensure lifetime: Deposition of volatilized material, such as sublimated material or particles, on the TPV cell could greatly reduce the efficiency and lifetime of the TPV cells by blocking their view to the heat source and causing cell overheating. In this project we developed and demonstrated an approach that reduces the deposition rate, ensuring long > 30 year life. Technoeconomic feasibility and commercialization: In collaboration with the project’s technical advisory board, we developed a technoeconomic model. The model shows that, at large scales (> 1GWh) the thermal battery technology is projected to reach a cost of energy stored below $10/kWh-e, with a cost per unit power < $0.5/W-e and a roundtrip efficiency of 50%. These results, along with the technical achievements in the project led to the creation of a startup company (i.e., Fourth Power) that is pursuing commercialization of the technology.

25 ENERGY STORAGE↗

Quantitative Risk Assessment for Fuel Cell Electric Bus Hydrogen Storage and Refueling Facility

It is necessary to understand the safety implications and risk mitigation options for fuel cell electric bus fleet deployment, especially for related facilities responsible for operations such as production, storage, compression, and dispensing of hydrogen for use by the buses. In this report, we present a quantitative risk assessment for a potential fuel cell electric bus fleet that was motivated by efforts to improve resilience at the Portland International Airport but can be applicable to a range of hydrogen case studies and use cases. We estimated risk for a facility that produces, stores, compresses, and dispenses hydrogen for the fleet of buses, with a focus on individual risk to people in terms of annual frequency of fatality. We considered the frequency of hydrogen leaks that could result in harmful physical outcomes like jet fires or explosions, and the consequences of those outcomes for people. We created customized fault trees to calculate the frequencies of different sizes of leaks and event sequence diagrams to calculate ignition probabilities for the various leak sizes. We also leveraged the HyRAM+ toolkit to use these inputs to calculate overall risk for the facility, which we separated into one section responsible for producing, storing, and compressing hydrogen, and one section responsible for dispensing the hydrogen to the buses. We found that the dispensing area seemed to have a higher risk than the production/storage/compression area of the facility, largely because of the inclusion of a component with a high leak frequency (the heat exchanger used to cool the hydrogen before entering the vehicle, to prevent overheating and expansion of hydrogen in the onboard tank). For the example production and refueling facility we evaluated and the data we used for the analysis, the leak frequency had a larger impact on the risk differences between the two sections on the facility, compared to the physical outcome consequence, which was slightly different due to the varying fuel conditions, but not substantially different. Actions can be taken to prevent these hazards (e.g., lowering leak frequencies in system components) or to mitigate the consequences if they do occur (e.g., installing barriers to protect people if ignition events occur). The choice of which actions to take depends not only on safety considerations but also on space, time, staffing, feasibility, and financial constraints. Therefore, the quantitative risk assessment approach can help understand relative risk contributions from different components, leak sizes, consequences, and human actions, to prioritize risk reduction strategies and balance these parameters. The outcomes of this report may be useful for a variety of stakeholders working in the hydrogen, transportation, vehicle, and aviation sector, including those responsible for aspects like facility design, operations, and regulations. There is not a single value of risk that determines whether a hypothetical system is “safe” or not. The insights about risk mitigations may be leveraged, and the quantitative risk assessment approach can be applied to other case studies to understand risk priorities and contributions specific to different FCEB and hydrogen facility uses.

08 HYDROGEN↗

Commentary: Our “heatshed” moment is now

We are living through a “heatshed” moment, a critical turning point in which heat must be rapidly addressed to protect health and livelihoods worldwide. The year 2024 was the hottest on record since global records began in 1850, and the past 10 years were the hottest decade in recorded history. Although extreme heat is the top weather-related killer in the United States, affecting livelihoods and economies, cities and nations dedicate more attention and resources to other climate hazards, such as hurricanes, floods, droughts, and wildfires. In this commentary, we argue that heat resilience must be rapidly advanced through heat mitigation, heat management, and heat governance efforts to ensure thriving communities in the face of an overheating world.

Extreme heat↗

Cool rooms for indoor heat resilience: Evaluating affordable cooling strategies in heat-stressed California homes

Extreme heat conditions pose significant indoor survivability challenges for resource-constrained communities, which often lack access to cooling, have poorly insulated homes, and face compounding socioeconomic vulnerabilities. Moreover, concurrent power outages worsen health risks and heat-related illnesses. It is therefore crucial to develop innovative and affordable cooling approaches to protect vulnerable populations. This study assesses the efficacy of “cool rooms”– a designated space within a home equipped with passive and low-power active cooling measures to maintain safe indoor temperatures during extreme heat events and power disruptions. Using a physics-based building energy modeling approach, we evaluate the efficacy of various retrofit packages in maintaining thermal safety within the cool room under recent extreme heat conditions. The results indicate that passive measures can reduce 64% of hours with unmet standard effective temperatures, while the combination of passive and low-power active measures with built-in batteries further cuts this to 86%. Nevertheless, these strategies remain insufficient to maintain indoor thermal safety during extended outages. In contrast, integrating a solar-powered mini-split heat pump, whose technical potential was evaluated in this study, reduces indoor air temperatures below the 28 °C overheating threshold and significantly improves indoor habitability. The localized cool room strategy also offers potential for grid resilience by reducing peak electricity demand by up to 70% compared to whole house cooling during heat waves. The findings can inform the development of actionable heat mitigation plans and retrofit policies for residential communities with relatively low adoption of air conditioning such as warm marine climates.

Cool room↗